Differences in clinical manifestations between cases stung by single-tentacle and multiple-tentacle box jellyfish over two decades

There are no routine laboratory investigations to identify jellyfish species and toxins in Thailand. Distinguishing clinical manifestation is important for medical care and also recommendations for the population. This study aimed to describe the clinical manifestations of box jellyfish stinging cases and determine differences between cases stung by single- (SBJ) and multiple-tentacle box jellyfish (MBJ). This retrospective study was conducted in Thailand. Data regarding injuries and deaths eligible for inclusion were those pertinent to stinging by box jellyfish under the National Surveillance System of Injuries and Deaths Caused by Toxic Jellyfish. All cases detected by the Toxic Jellyfish Networks were investigated. There were 29 SBJ, 92 MBJ, and 3 SBJ/or MBJ cases in the period 1999 to 2021. In about half of the cases in each group had abnormal heart rates and about one-third had respiratory distress. The SBJ group had a high proportion of pain in the other parts of the body (38.2%), abdominal cramps (13.8%), fatigue (24.1%), anxiety/agitation (24.1%), and there was no death. The MBJ group had a high proportion of severe pain and severe burning pain at the site of the wounds (44.3%), swelling/edema at the affected organs/areas (46.8%), collapse/near-collapse (30.4%), worse outcomes (9.8%), and 9.8% deaths. In comparison to the MBJ group, the SBJ group were 13.4 times (95% Confidence Intervals of Relative Risk: 4.9, 36.6) and 6.1 times (1.2, 31.4) more likely to have pain in other parts of the body and abdominal cramps, subsequently. MBJ group was 1.8 times (1.4, 2.2) more likely to have pain at wounds than the SBJ group. Some initial symptoms might make health professionals misdiagnose SBJ as MBJ stinging. The Irukandji-like syndrome that appeared later among SBJ cases is the clue for correct diagnosis. These results are useful for the improvement of diagnosis, medical care, and surveillance.